A network approach to Titan Options

[karolp]

So this is a supplement to this thread:

http://www.unmannedspaceflight.com/index.php?showtopic=5819

And goes deeper into several aspects in the particular case of future Titan missions - to better illustrate some points and to actually provide some speculation on what really could be done on such a mission. I do realise there are rover-specific threads and threads about what actually IS planned, however I still think we might need a place for a fresh perspective putting certain financial and technical limitations aside, just to think "out of the box" for a minute.

So the main idea is: NOT a single spacecraft that may or may not succeed and then provide us only with limited results and finally become history like they all did. The idea is a NETWORK of spacecraft that COOPERATE with each other INTENTIONALLY and right from the start and not by coincidence and also provide a lot of redundance and inspection capability for worst-case scenarios.

I do realise what I propose may be very expensive or some of the technologies may still not exist yet at all. However, I believe it is better to establish a lasting telepresence on Titan and gain a lot of insight than to send something cheap and expendable and then wait another decade for a new opportunity of a flagship mission to come.

Also, at the end I suggest some ways of reducing the cost and developing new technologies or rather accelarating development that is already in progress because this is exactly what we did when we actually made PROGRESS in the past.

So, the idea is as follows - please comment on it freely:

The entire mission is comprised of:

1. orbiter

Capable of extremely broadband transmissions with multi-threading to be able to constantly uplink from all ground spacecraft without effort and also able to LEAVE Titan orbit once the ground mission is complete (meaning the last of the bunch of ground spaceraft stops working).

2. TWO rovers

Each sent to a target location carefully selected AFTER getting there, not based on incomplete and preliminary reconnaissance from the previous mission. The rovers would be sent one at a time so that if the first one fails, we could examine the likely cause and avoid it. The timespan between orbit insertion and rover release should be such that a detailed scientific analysis of possible target areas is largely complete because landing a rover is an irreversible process and after it lands it can only go a short distance.

3. TWO hydrofoils

Landing a short-lived Huyghens class lander on liquid still gives as something like a stationaly lander. With a protected hydrofoil however we could land on a lake and quickly cruise coast to coast while gaining enormous insights into what is there.

4. TWO mini-submarines

Attached to each hydrofoil and detached to explore what is going on IN the liquid reservoir and even at the bottom of the lake. The submarines should be largely independent so that even if the hydrofoils malfunction or shut off, the subs should still be able to broadcast. They could also be made capable of submerging and reemerging multiple times to limit hardware wear-off or even re-attach to the hydrofoils for quick transport to other areas within the lake.

5. TWO mini-choppers

I suppose choppers would be better than airplanes because they HOVER above an area and take photos, do not run into obstacles as quickly and it is easier for them to take off again after they landed. The purpose of the choppers would be to double as "stationary" landers that could be "landed" many times in many different areas and provide some basic insight - and unlike real landers, take off again and go somewhere else quickly after they are done.

6. TWO mini dirigibles with PROPULSION, NOT passive balloons

The purpose of these would be to provide airborn insight into areas which can no longer be reached by rovers once they landed or would take too much time for the choppers to reach. Both the dirigibles and the choppers would be capable of inspecting the rovers and possibly the hydrofoils in much greater detail than the orbiter, as well as arriving on site independently of the orbiter's availability.

After the last ground spacecraft goes silent the orbiter would leave Titan orbit and move on to provide detailed cartography of Enceladus which would require much less energy than high-speed transmissions from the ground spacecraft and would be suitable as an additional goal when the energy is low and the spacecraft can become inoperable any moment.

Probably by now you think this is ridiculous because the amount of money involved would be enormous. It would if we did it the way we do missions NOW.

But before I move on to talk about how we can make such a thing more affordable, just think about the tremendous and lasting scientific gain such mission would provide and the kind of background for future missions should we decide to continue, not to mention various technological spin-offs that could later be used on Earth.

You may also think this is a completely crazy idea because we would need technology that does not exist yet. Or does it? We are already developing AI in military planes and vehicles and taking it one step ahead to be capable of totally independent activity and cooperation somewhere far away would definitely not be an idea that would be frowned upon by the military or any kind of organisations that need telepresence in disaster areas or environments on Earth that are not readily accessible for living and breathing humans.

Now - how do we make it affordable?

Actually aiming at developing something that could also be used on Earth is one of the ways to take the cost out of the equation. The AI could be developed outside of NASA and used on Earth to cover the cost of research even before the mission is launched into space. NASA would simply grab the tech and put it into its spacecraft rather than paying for the full development. All one would have to do is to assure that the government tells the military to accelerate the development of something that is already in progress and can be used by the military independantly.

The other obstacle is developing cryoprotection technologies that would ensure that those things would function on Titan and not wear off to quickly. Still, protecting things from cold temperature or avoiding excessive thermal exchange is something than can widely be used by humans on Earth - be it food storage, high mountain exploration or Antarctic research.

The final point after AI and cryoprotection is hardware. Again, we do not have to make a completely new design just because something goes somewhere. Of course it needs to adapted to the environment, but a small chopper used as a reconaissance drone by the military could have the taken guts out and replaced with cryo-optimised guts and covered with cryo-protection and flown to Titan without re-inventing the whole chopper from the scratch.

You may now say that this still does not solve the launcher problem because the whole package however small it may be is still rather heavy and Titan is very far away and we do not have heavy-lift vehicles with that capability yet. But do we really need to send it all at once? Automated docking of small demonstration hardware in orbit has been practiced by the Japanese in the late 1990s. Instead of re-inventing the rocket, we can just send two Ariane 5 launchers in two separate flights, dock the package in orbit and then ignite a powerful ion engine to really accelerate it towards its destination.

There is a lot of redundancy and failsafe mechanisms in this. As you can see there are lots of possibilites of acquiring a lot of scientific insight and even if some things go wrong, the mission is still a huge leap forward in our understanding and the money invested does not go into a black hole even if some of the objectives are compromised by unforseen events. Even after the mission is over, the technologies developed for it can be used on Earth extensively and balance the cost whatever it might have been. The AI can also be reused on Mars or any object which is to far for real time operation of rovers and with the cryo-protection added, we can easily re-use it on Europa, Enceladus or any other body without having to invest anything in the development again, just another launch and manufacturing another set of hardware from existing blueprints.

OK, I had no idea that would make such a humongous post - I hope someone in the forum gets to the end and tells me his or her own views regarding my idea of how we could get the most out of a mission to Titan.

[dvandorn]

To get that many things out to Titan, deliver them in one piece, and be able to keep them running for more than a day or two, takes a lot of mass. We're not talking two Ariane 5 launches, here. We're talking a dozen. And there is no such thing as a "really powerful ion engine" in existence -- ion engines are low-thrust, takes-a-long-time-to-get-there propulsion solutions, and will be for decades to come.

I would absolutely love to see all of the Titan probes you suggest, Karol. But realistically, you're talking about a half-trillion-dollar project. With as much as there is to explore in the solar system right now, I can't see putting that much money into a single moon, no matter how interesting it is.

-the other Doug

[karolp]

Hi Doug,

Thanks for a swift answer and it largely is what I expected. But let us go very specific here:

1. just how much mass are we talking here? The rovers do not have to be the size of a car and the hydrofoils are not passenger hydrofoils and the same applies for the rest of the stuff I am suggesting. Let's stick to reality - let's compare the mass to the Cassini spacecraft which HAS been sent to Saturn at an acceptable cost.

So it goes like this:

2 Sojourner-mass rovers but fitted with better instruments and cryoprotection
2 hydrofoils that can really be as small as allowed for not being affected too much by waves etc.
2 choppers which can be as small as allowed for them not to be smacked around by winds
2 dirigibles - same as above applies here
2 tiny submarines which just need to be manouverable

Let's assume that our orbiter goes on a separate launcher and docks with the package in orbit. Are we talking about 2 Cassinis on 2 Titan 4Bs here or am I still way out of the league? And by the way - what is more capable of sending s/c to Saturn - a Titan 4B, Delta IV heavy or Ariane 5?

2. Why don't we have decent propulsion for spacecraft? Is it the matter of power consumption or anything else? Wouldn't a bunch of RTGs do the trick in providing power to a more efficient ion engine or anything similar?

3. We assume that all technology is developed outside of NASA by the military (which is already doing the AI) and private companies (which might be interested in developing cryoprotection solutions that could also be used on Earth which would cover the costs of research into the technology). NASA would only have to put the AI, hardware (which can also be some Earth technology derivative since we have similar pressure etc. on our planet) and the cryoprotection together and pay for the launcher.

Does it make some sense now? What do you think?

[dvandorn]

Let's add a little more of hard reality to your analysis, here...

"2 Sojourner-mass rovers but fitted with better instruments and cryoprotection" -- the better instruments and cryoprotection will add mass. I'd guess that these two rovers plus the descent system needed to land them will mass at least as much as Huygens, if not quite a bit more. Plus, add a power system that will keep these rovers going for more than a few hours, and you're talking considerably more mass than Huygens. (Solar cells, as used by Sojourner, aren't really an option on Titan's surface, what with the extreme distance from the Sun and the filtering of Titan's heavy atmosphere.)

"2 hydrofoils that can really be as small as allowed for not being affected too much by waves etc." -- again, each needs its own separate power supply, radio communications links, and also a landing system capable of delivering them in usable condition to a liquid environment. Off the top of my head, I'd have to think this would mass more than Huygens, perhaps even drastically.

"2 choppers which can be as small as allowed for them not to be smacked around by winds" -- these can be smaller than the rovers and the hydrofoils, but what kinds of instrumentation can you fit on a really small chopper? A camera? I doubt you could fit a multispectral camera in such a small platform, much less a useful spectrometer or magnetometer. So, yes, you could deliver a couple of little toy choppers with webcams in them for pretty cheap, but would they be worth all that much, scientifically? Anything that would let you do extensive science is going to be getting you into multiples of Huygens' mass. And as for all of these probes, you need to design a power system that will let them operate for more than an hour or two.

"2 dirigibles - same as above applies here" -- and same as above applies here, too.

"2 tiny submarines which just need to be manouverable" -- and again, how much in terms of sensor technology, power systems, cryoprotection, etc., can be built into a tiny submarine? Each one would have to be at least Huygens' mass, if not more, just to contain the systems needed to operate and do any reasonable science.

Altogether, you might be able to piggyback a couple of these things, but your communications relays would already have to be in place (requiring still more launches), and you literally could not send all of these 10 suggested probes on a single lander, since some of these things would need to head for polar lakes while others would best be targeted for the equatorial sand seas and for suspected cryovolcanic locations.

I stand by my concept that you would need a dozen launches to put all of these assets in place. If not more.

And please note the other thread in re ion engines -- to send large payloads long distances, you need to either use a lot of reaction mass to get there within a reasonable (less than a decade) timeframe, or you use low-thrust engines (which is all that ion engine technology offers at present) and take 20 to 50 years to get out to Saturn. And actually, RTGs don't put out the kind of amperage you really want to drive ion engines. If you're going to go that route, you need to use actual nuclear reactors, and I will refer you to the failure of the Prometheus project to gain funding in the early days of this decade as to why we will likely not go that way any time soon.

-the other Doug

[djellison]

As with the other thread - this is pointless - and it's sci-fi engineering. Not here please.